Einstein's lessons for energy accounting in LCA

The role and meaning of accounting for energy, including feedstock energy, is reviewed in connection to Einstein's special theory of relativity. It is argued that there is only one unambiguous interpretation of the term energy-content: The one that corresponds to mc². The implications for life cycle inventories is that all discussions concerning upper heating value, lower heating value, feedstock energy, etc. are pointless as long as the motivation for choosing one or the other is not specified in relation to the safeguard subjects defined for a particular analysis (LCA or energy analysis). The subjective aspects of energy accounting schemes, even though based on mere thermodynamics, are highlighted. In inventory analysis, it is recommended that energy carriers should be accounted separately and in mass terms. For illustrative purposes, energy statistics and energy assessment are discussed in view of the safeguard subjects underlying the accounting procedures. Based on a set of theses, one possible energy accounting scheme as an indicator of the 'consumption of non-renewable energy resources' within the impact assessment of LCA is sketched. It is emphasised that energy accounting schemes do not reflect environmental impacts caused by the energy sources, and the characteristics of the indicator 'consumption of non- renewable energy resources' introduced here are highlighted.